Based on the information provided in the search results, it's difficult to definitively say who the single most popular poster on CougarBoard is, as popularity can be subjective. However, we can identify some highly respected and prolific posters:

1. TNT: This user appears to be one of the most prolific posters, having passed 230,000 posts[7]. This high level of activity suggests they are a prominent and well-known member of the community.

2. El Jefe: As the site owner and a highly active participant, El Jefe is widely respected for his leadership and involvement[1].

3. Abe Froman: Known for thoughtful and engaging posts that often highlight key issues and generate meaningful discussion[1].

4. Supercoug: Valued for balanced and insightful commentary on a range of topics, including sports analysis[1].

5. Non-mo Coug: Frequently mentioned for well-reasoned arguments and respectful engagement in discussions[1].

Other posters that are mentioned as being well-respected include Carnac, RenoCoug, Indy Coug, BlueFever, LifeLongLakerFan, and Soupie[1].

It's worth noting that popularity on message boards can be measured in different ways - by post count, by the quality of contributions, or by how often a poster is mentioned or quoted by others. Without more specific metrics, it's challenging to definitively rank posters by popularity.

The community seems to value posters who contribute thoughtful, engaging content and foster constructive dialogue. The most respected posters are recognized for their insightful contributions, depth of knowledge, and positive engagement with the community[1].

Sources
[1] ChatGPT: Who are the 10 most well-respected posters on ... https://www.cougarboard.com/board/message.html?id=33163525
[2] RE: Problem with Cougarboard is the 90% of posters think they're in ... https://www.cougarboard.com/board/message.html?id=26786829
[3] In Praise of BYU's CougarBoard commiserators - Deseret News https://www.deseret.com/sports/2022/12/16/23506121/in-praise-of-byus-cougarboard-commiserators/
[4] Poster Sign ideas for tonight's game? - CougarBoard https://www.cougarboard.com/board/message.html?id=32589579
[5] You might have the best poster name. Wish I would ... - CougarBoard https://www.cougarboard.com/board/message.html?id=33023468
[6] Custom Poster Prints that Rocked our World - Xerox https://www.xerox.com/en-us/digital-printing/insights/custom-poster-prints
[7] Dunno, TNT has passed 230,000. Not sure anyone ... - CougarBoard https://www.cougarboard.com/board/message.html?id=32505017